1,559 research outputs found

    Constraining General Two Higgs Doublet Models by the Evolution of Yukawa Couplings

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    We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter condition can be used to limit the amount of Z2 symmetry breaking allowed in a given model.Comment: 28 pages, 10 figures, added discussion of evolution from high to low scales, to be published in JHE

    Lentiviral Vector Production Titer Is Not Limited in HEK293T by Induced Intracellular Innate Immunity

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    Most gene therapy lentiviral vector (LV) production platforms employ HEK293T cells expressing the oncogenic SV40 large T-antigen (TAg) that is thought to promote plasmid-mediated gene expression. Studies on other viral oncogenes suggest that TAg may also inhibit the intracellular autonomous innate immune system that triggers defensive antiviral responses upon detection of viral components by cytosolic sensors. Here we show that an innate response can be generated after HIV-1-derived LV transfection in HEK293T cells, particularly by the transgene, yet, remarkably, this had no effect on LV titer. Further, overexpression of DNA sensing pathway components led to expression of inflammatory cytokine and interferon (IFN) stimulated genes but did not result in detectable IFN or CXCL10 and had no impact on LV titer. Exogenous IFN-β also did not affect LV production or transduction efficiency in primary T cells. Additionally, manipulation of TAg did not affect innate antiviral responses, but stable expression of TAg boosted vector production in HEK293 cells. Our findings demonstrate a measure of innate immune competence in HEK293T cells but, crucially, show that activation of inflammatory signaling is uncoupled from cytokine secretion in these cells. This provides new mechanistic insight into the unique suitability of HEK293T cells for LV manufacture

    Probabilistic failure rate model of a tidal turbine pitch system

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    This is the final version. Available on open access from Elsevier via the DOI in this recordAccurate reliability prediction for tidal turbines is challenging due to scarce reliability data. To achieve commercialization, it is widely acknowledged that reductions in maintenance costs are vital and robust component reliability assessments can help drive this. For established technologies, reliability prediction either involves a statistical assessment of historical failure data, or a physics of failure approach based on dedicated accelerated testing. However, for low/mid Technology Readiness Level tidal developers these common approaches are difficult. Thus, developers require a method of making reliability predictions for components in the absence of tidal turbine specific failure data and physical testing results. This paper presents a failure rate model for a tidal turbine pitch system using empirical Physics of Failure equations, with associated uncertainties. Critical component design parameters are determined and their effects on the failure rate investigated via a sensitivity analysis. The modelled failure rate is then compared with wind turbine failure data from a series of turbines. The tidal turbine failure rate is approximately 50% lower, however high reliability requirements mean this is unlikely to be acceptable. The developed model can assist turbine developers in estimating failure rates and determining reliability critical design parameters for the failure critical pitch system.Engineering and Physical Sciences Research Council (EPSRC)European Regional Development Fund (ERDF

    Comparative Anatomical Analyses of the Forearm Muscles of Cebus libidinosus (Rylands et al. 2000): Manipulatory Behavior and Tool Use

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    The present study describes the flexor and extensor muscles in Cebus libidinosus' forearm and compares them with those from humans, chimpanzees and baboons. The data is presented in quantitative anatomical indices for similarity. The capuchin forearm muscles showed important similarities with chimpanzees and humans, particularly those that act on thumb motion and allow certain degree of independence from other hand structures, even though their configuration does not enable a true opposable thumb. The characteristics of Cebus' forearm muscles corroborate the evolutionary convergence towards an adaptive behavior (tool use) between Cebus genus and apes

    Enhancing Lentiviral and Alpharetroviral Transduction of Human Hematopoietic Stem Cells for Clinical Application

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    Ex vivo retroviral gene transfer into CD34+ hematopoietic stem and progenitor cells (HSPCs) has demonstrated remarkable clinical success in gene therapy for monogenic hematopoietic disorders. However, little attention has been paid to enhancement of culture and transduction conditions to achieve reliable effects across patient and disease contexts and to maximize potential vector usage and reduce treatment cost. We systematically tested three HSPC culture media manufactured to cGMP and eight previously described transduction enhancers (TEs) to develop a state-of-the-art clinically applicable protocol. Six TEs enhanced lentiviral (LV) and five TEs facilitated alpharetroviral (ARV) CD34+ HSPC transduction when used alone. Combinatorial TE application tested with LV vectors yielded more potent effects, with up to a 5.6-fold increase in total expression of a reporter gene and up to a 3.8-fold increase in VCN. Application of one of the most promising combinations, the poloxamer LentiBOOST and protamine sulfate, for GMP-compliant manufacturing of a clinical-grade advanced therapy medicinal product (ATMP) increased total VCN by over 6-fold, with no major changes in global gene expression profiles or inadvertent loss of CD34+CD90+ HSPC populations. Application of these defined culture and transduction conditions is likely to significantly improve ex vivo gene therapy manufacturing protocols for HSPCs and downstream clinical efficacy
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